The present invention relates generally to apparatus and method for testing a joint replacement device and pertains, more specifically, to testing the respective components of a joint replacement device in articulation relative to one another under a load.
Artificial or prosthetic devices for replacing defective joints in humans have been the subject of extensive research and development efforts for many years, particularly with regard to hip and knee joints, and more recently with spinal joints. In the design of such devices, it is advisable to subject the components of each new design to static and dynamic testing. Such testing is prudent in that it ensures that a particular design will not fail prematurely. Thus, a need exists within the medical equipment industry to assess the endurance properties of components of joint replacements.
While machines suitable for testing artificial or prosthetic hip and knee joints are known and are available to provide a variety of loading and articulation combinations, such machines have several shortcomings, including large size, significant cost (both of purchase and maintenance), and slow speed. Moreover, many joint testing devices have been developed specifically for use with hip and knee joints, and in that respect are unsuitable for use with the growing number of spinal implants. The need to retrofit or completely redesign such machines for use with spinal implants increases the cost and, in some cases, the size of the machines.
There are some devices that purport to address some of the above-described shortcomings. For example, Enduratec (Minnetonka, Minn.) manufactures at least one Spinal Disc Implant Wear Testing System, the respective capabilities and features of which are summarized at http://www.enduratec.com/testapp.cfm/tid/29 and http://www.enduratec.com/testapp.cfm/tid/27. While utilizing newer technologies to increase speed and minimize size, these devices are nevertheless costly and complicated in function for many uses.
Therefore, there is a need in the field for new approaches to provide a joint replacement device testing machine and method that efficiently effect articulation of replacement joint components under a load.